What's the point of the 32 bit nonce?

[ivarbug]

50GH/s Butterflylabs' rig could run through every possible nonce in 100ms. If so what's the point of it? What makes getting a valid hash so difficult? Is it because most of the time no valid hash exists for current input data combined with every possible nonce? Or what am I missing?

[caveden]

There are other things you can change to attempt other hashes.
The timestamp, for example, is quite flexible.
And the coinbase is controlled by the generator. There's this extraNounce field people are putting there.

[ivarbug]

Ok, so we have a timestamp. What else? Because timestamp manipulation wouldn't add up much. A set of state of the art rigs and we loop through 2^32*timestampMargin in no time. So when mining equipment gets better and difficulty goes up we end up in a situation where mining success = who gets a valid hash submitted first?

And the coinbase is controlled by the generator. There's this extraNounce field people are putting there.

Can you explain this further? I have no idea what you were trying to say with this.

[tawitsa]

i would be interested to know if extranonce exists in last block version and how long (in bits) is it.

[scintill]

And the coinbase is controlled by the generator. There's this extraNounce field people are putting there.

Can you explain this further? I have no idea what you were trying to say with this.

The first transaction in the block is called the "generation" or "coinbase" transaction, which serves to say where the new coins should be sent.  Since these are new coins with no history, no "input" has to be specified.  Arbitrary data can be put in there instead.  It has some structure by convention, but I don't think there are any hard requirements.  The so-called "extraNonce" is put in here, to solve the problem you pointed out.  It can be from 2 to 100 bytes long, plenty of extra size to solve this problem.

https://en.bitcoin.it/wiki/Transaction#Generation
http://blockchain.info/tx/f31d440dc9831ed2f7961a32a06e864b417429f0b9b5b824a8c273b33d7946a1?show_adv=true see CoinBase at bottom

[ivarbug]

Oh yeah, that makes sense. Thanks.